Have you all forgot the basics of sea ice formation? RoxTheGeologids, macid, slow wing?
Sea ice is densest at freezing point, and thus does not freeze in the same way that lake ice does. So slow wings "model" is patently wrong, and the increased density of surface waters as they cool and sink create enough convection to stir up the top tens of meters of ocean, getting all that heat to the surface.
Which is not to say that wave action will also create turbulence.
The current ice-free areas have a fair amount of wind according to NullSchool, but more importantly, the air temps are nowhere near low enough to start freezing.
I think that's what I said. I don't understand where I went wrong with my statement. Please edify!
Well, that's not what I read. In this comment,
As ice forms the ice is fresher than the seawater, the salts partitioning into the water. The denser cold, salty water sinks, creating convection. This causes the upper mixed layer to, well, mix, and deepen. My guess is that it slows down the ice formation, but the mechanism needs ice to be growing before heat starts to move up from deeper layers.
you talk about the formation of ice as causing the sinking of the upper layers, and you claim that ice not only needs to form but needs to be growing before heat starts to move up.
So you are claiming a mechanism for heat transfer to the surface that is based on salt extrusion when ice forms (more salt = more weight).
But the fundamental mechanism of sea ice formation (which you seem to have forgotten here) is that sea water is densest at freezing point, which means that before any ice has time to form, the surface water starts sinking and mixing downwards, and the underlying warmer waters start to move up.
This is presumably what is happening in all the open areas of the arctic right now. Very cold air is blowing in from the south (from Siberia) and from the ice itself, but the air heats up very rapidly over the open ocean where the sea surface temperatures are above freezing.
The first image below shows status this morning from Nullschool, but it's essentially unchanged over the last week or so. The two blue arrows show where cold winds are blowing in over open ocean. The red figures show air temperatures at surface (in Centigrades), and the one in the middle has sea surface temperatures in paranthesis.
The thing to notice is that the air warms very considerably when blowing in over the (much warmer) ocean and that the surface of the ocean is hovering just over the freezing poing of c.a. -1.8C. As I said, this situation has been unchanged this week every time I've checked.
The second image is a very crude attempt at describing the movement of air and water at the interface. Cold air flows in over the warmer ocean, causing the air to get warmer and start to rise, allowing other cold air to sink towards the surface. The wind is carrying this turbulence forward all the time.
At the same time, the relatively static ocean waters cool at the surface and start sinking, allowing warmer deeper waters to rise.
This will continue until there is not enough heat within easy reach to keep the near-freezing waters from sinking before they freeze. This can happen because the ocean has run out of heat, or when the air is cold enough to override the sinking process (at the anecdotal -11C).
The wind is very important here, it keeps carrying the heat away from the surface, and will of couse also increase the water turbulance through wave action.